The present invention relates to control devices for electrical power circuits like lighting and appliance circuits in residences. In recent years a large demand for automatic and/or remote control of residential lighting has developed as a result of the increased crime rate involving home invasions. Automatically timed control of lighting has become widely accepted as a significant deterrent for prevention of home invasion. Also, the remote operation of lights, either automatically, from an intrusion alarm system, or from a remote location such as a bedside unit, is a desirable feature of a home protection system.
One type of automatic light timer commonly available today has motor driven mechanically activated switches. The least expensive type provides a single "on" time selection and a single "off" time selection for each 24 hour period. Some mechanical timers provide for the selection of one hour "on" or "off" intervals that can be arranged in any pattern. The pattern is repeated every 24 hours. The most popular timer type is self contained, with a two-prong plug interval with a housing therefor for directly plugging into the usual household electrical outlet. The housing also has an integral socket for plugging in the lamp or appliance to be controlled. Another timer type has a power cord and is designed for setting on the floor or table top. Some manufacturers offer timers for permanent wall mounted installation to control lighting fixtures. To further enhance the usefulness of automatic light timers as a deterrent against home invasions, some timers have a feature that alters the actual "on" time from day to day so that a more probable "lived in" pattern results.
Mechanical motor driven timers have achieved great popularity because of their low cost. However, because of the limitations of mechanical systems, mechanical timers presently in use suffer from a number of disadvantages. Thus, mechanical timers tend to be unreliable and noisy (especially after some period of use), forcing many owners to abandon their use in quiet areas such as studies and bedrooms. Mechanical timers are also large and bulky and therefore have not lent themselves widely to convenient table-top use with "decorator" type styling. The use and bulk of mechanical timers precludes their installation into a flush device electrical box, such as commonly houses wall switches for the control of outdoor or ceiling lighting fixtures.
Inexpensive mechanical timers have "MANUAL/AUTOMATIC" settings on a switch selector. When the timer is in the "AUTOMATIC" mode usually the light cannot be turned on or off without taking the timer out of the "AUTOMATIC" mode. Thus if it is desired to change the light from its present automatically programmed state to the opposite state (ON to OFF or OFF to ON) the user must remember to return to "AUTOMATIC" before leaving the room if he wants programmed control to continue. However, some mechanical timers heretofore developed have an automatic override feature where the automatic control returns to operation automatically when the manual setting and automatic setting subsequently correspond.
There has also been marketed recently a relatively expensive electric timer which is sufficiently compact that it fits into a toggle wall switch opening. However, this timer completely replaces an existing single toggle switch station and the cover plate thereat and is thus not mountable upon or behind any selected station of a multi-station toggle switch installation using a conventional cover plate, which is most desirable for the most successful marketing of a timer of the type being described. Also, this electric timer is not flexibly programmable by the user; rather, fixed individual programming timing modules are initially installed by the manufacturer which are changed by an electrician by the substitution of a different module to effect a change in the light turn-on or light turn-off program.
It is, accordingly, an object of the invention to provide an electric timer which has a housing assembly construction which enables it to be mounted in place of a toggle switch installation associated with any station of a single or multi-station cover plate without requiring the replacement of the cover plate or interferring with the toggle switches of the other stations which may be associated with the cover plate.
A related object of the invention is to provide a timer as described which has manual controls which enable the timer to be easily programmed by the user to provide a wide selection of ON and OFF time intervals.
Still another object of the invention is to provide a timer satisfying any one or more, and preferably all of the previously stated objectives and which can be made to sell for a price which is attractive to a mass market, and which can be easily installed and used by simple instructions understandable by the average home owner.